.travis.yml in omml2mathml-0.0.2 vs .travis.yml in omml2mathml-0.0.3

@@ -1,10 +1,10 @@
 dist: trusty
 language: ruby
 sudo: false
 
 before_install:
-  - gem install bundler -v 1.16.1
+  - gem install bundler -v 2.0.1
 
 rvm:
   - 2.5
   - 2.4
   - 2.3